ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: Null check operator used on a null value

Question

Hi Everyone i am facing an issue (null check operator used on null value) when i remove this operator it gives me Error here is my code

Future<void> getDirectionDetails() async {
    var pickUpDetails =
        Provider.of<AppData>(context, listen: false).currentPickupAddress;
    var destinationDetails =
        Provider.of<AppData>(context, listen: false).destinationAddress;

    var pickUpLatLang =
        LatLng(pickUpDetails!.latitude!, pickUpDetails.longitude!);
    var destinationLatLang =
        LatLng(destinationDetails!.latitude!, destinationDetails.longitude!);

    showDialog(
        context: context,
        builder: (BuildContext context) =>
            ProgressDialog(status: "Please Wait"));

    var locationDetails = await GeocodeHelper.getDirectionDetails(
        pickUpLatLang, destinationLatLang);
    print(locationDetails.EncodingPoints);
    Navigator.pop(context);
  }

And this is my Class from where i am getting this information.

class AppData extends ChangeNotifier {
  Address? currentPickupAddress;
  Address? destinationAddress;

  void updatePickupAddress(Address pickup) {
    currentPickupAddress = pickup;
    notifyListeners();
  }

  void updateDestinationAddress(Address destination) {
    destinationAddress = destination;
    notifyListeners();
  }
}

Can you post your entire error message or stack trace to better understand the error. — srihari ayapilla, Jun 16 '22 at 07:39
Well, what do you *want* to do when these fields are `null`? We cannot magically summon correct geo-coordinates for you. You have to decide how to handle not having any. — nvoigt, Jun 16 '22 at 08:48

score 0 · Answer 1 · answered Jun 16 '22 at 07:40

I guess the problem is in this block of code

    var pickUpLatLang =
        LatLng(pickUpDetails!.latitude!, pickUpDetails.longitude!);
    var destinationLatLang =
        LatLng(destinationDetails!.latitude!, destinationDetails.longitude!);

See you are force unwrapping the pickUpDetails,latitude and longitude without checking if there value is null or not which gives the issue.

you can try the following

    var pickUpLatLang =
        LatLng(pickUpDetails?.latitude??0, pickUpDetails?.longitude??0);
    var destinationLatLang =
        LatLng(destinationDetails?.latitude??0, destinationDetails?.longitude??0);

Of course I'm assuming that latitude and longitude are of type int, if not please provide the suitable default value.

Thanks For your help but it will fix this error and by providing 0 as Latitude and longitude it will cause issue where i am sending lat and long details to get some output using lat long. — Uzair Ahmad, Jun 16 '22 at 08:15
It will only provide zero in case the latitude or longitude is null, you can try another solution by defining a default location (like user current location) then send its latitude and longitude in case of null — Ahmed Adel, Jun 16 '22 at 10:20

score 0 · Accepted Answer · answered Jun 16 '22 at 08:57

I've just recheck my code and found an error from where i was getting my latitude and logitude values. Before

currentData.latitude = response["result"]["geometry"]["location.lat"];
currentData.longitude = response["result"]["geometry"]["location.lng"];

After

currentData.latitude = response["result"]["geometry"]["location"]["lat"];
currentData.longitude = response["result"]["geometry"]["location"]["lng"];

ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: Null check operator used on a null value

2 Answers2